(Hello?) I say, hoping the mind will hear me.

Emotions. Not mine. Surprise isn't one of them. Well, not completely. The other mind is surprised about something, but he's clearly not shocked that I've just spoken to him.

(Zach? Why so quiet this morning?)

He seems concerned about me.

No, not about me. About Zach. I guess that Zach is the name of the kid I'm in today.

(I'm...not Zach,) I tell him. (Who are you, anyway?)

The mind laughs. (Zach, you know who I am. I've been in your head for the past two years.)

Frustration, even anger, clouds my response. (Maybe ZACH knows, but I don't! I've only been here for what, five minutes? However long it's been since we woke up, anyway.)

There's a pause before the mind responds. (You do seem off today, Zach. And I can't detect your thoughts, except what you've aimed at me.)

I'm almost glad that he's confused. Even though he's done nothing to deserve it. Whoever he is, he seems to know Zach, and if he's telling the truth, they've known each other for two years.

(That's. Because. I'm. Not. Zach,) I tell him, emphasizing each word. Then, I add, (My name is A.)

Maybe he can feel that I'm telling the truth, or at least, he can feel that I'm not lying. (And where is Zach?)

I note that he doesn't introduce himself, but I'm too wrapped up in my desire for information-any information-that I don't press it.

He does, however, try to reach out with his mind towards me. Not just communicate, but I get the distinct sense that he's trying to figure out what thoughts I am not saying. Like, I don't know, read my mind.

Can he do that?

(I don't know,) I tell him. (Asleep, maybe?) I can feel his disbelief.

(Who are you?) he asks me.

(I told you. My name is A. Zach isn't here, clearly, but I am. At least, for the time being.) It's my first chance to explain everything, to tell someone what's been going on my entire life. (Look, if everything goes the way it normally does, this Zach will be back tomorrow. But he probably won't remember much of today,) I begin.

He interrupts me, his response is sudden and furious. (WHAT HAVE YOU DONE TO MY HOST?!) he thunders.

It's enough to make me jump, except I can't. Well, I suppose that I can mentally, because I do just that.

(Hey! Look, I don't know anymore than you do about where Zach is. But I'll tell you what I do know if you can answer some questions,) I offer.

I can feel the mind's distrust. (No. Listen here, A. You will tell me everything that you know, and then I will tell you what you NEED to know.)

(That hardly seems like a fair deal,) I grumble.

(It's the best you're going to do,) the mind shoots back.

(Can I at least have your name?) I ask him. (You have mine, after all.)

Maybe it's stupid, but I want to think of him as something other than "the mind".

Besides, it's true that he already knows my name.

The mind pauses for a minute before saying, (My name is Tolgar Three-Two-Four of the Hett Simplatt Pool. You may address me as Tolgar.) In a more mild tone, he adds, (It's what Zach calls me.)

(Fine, Tolgar.) I pause, not sure how to begin. It's not like I've ever told anyone this before. Or, anyone who would believe me. (Like I said, my name is A. I'm here because, for as long as I can remember, I've woken up inside of a different body every day of my life. It's always been someone my age. For one day, that body is mine. I try to make it a normal day for that person, not disrupt anything. I don't know what happens to that person afterwards, or where they go while I'm there. I just know that it's always a different person, always my age, and always for a twenty-four hour period of time.)

The mind-I mean, Tolgar-seems to take a minute to process this. When he speaks again, it's a mere, (I see.)

I aim a laugh at him. Talking this way, mind to mind, isn't much different than talking out loud. I can even feel that his "voice" differs from that of Zach's, and I wonder what mine sounds like to him. Probably not the same as Zach.

(You believe me?)

(I can tell that you believe what you are saying, and as any thoughts that are not directed towards me are not available for me to see, I can either conclude that Zach has gone crazy during the night and has also managed to hide his thoughts from me-which, I might add, is something he stopped attempting after six weeks of being my host-or that you are telling the truth. And, A, the truth seems far more likely,) Tolgar says, matter of factly.

(Yeah, well, it's not like I ever told anyone this before. They wouldn't believe me.)

(They certainly wouldn't, but I am not human, and I have the advantage of being able to read your emotions, if not your thoughts. As I just told you, I can tell that you aren't attempting to deceive me, so I am choosing to believe that what you've told me is true. Besides,) he added, (You sound nothing like Zach, so even if he was trying to make all of this up as some sort of prank or ruse, he would not have succeeded thus far.)

(I'll take your word on that,) I tell Tolgar. (Usually, the memories come with the bodies, but I didn't know anything about this body today, not even his name. Or if it was male or female.)

Tolgar took a minute to digest this. (I have some theories about that, but as you told me your story, I suppose that I should keep my word and tell you mine.)

(That would be the decent thing to do,) I agree.

Tolgar laughs. (First, you should know that I am not human, but I imagine that you might have suspected as much.)

(Kind of,) I admit. (The whole thing about the pool. But that wasn't exactly forefront in my brain.)

Another chuckle. (I am an alien known as a Yeerk. In my natural state, I resemble a human slug, though perhaps twice the length of an average slug. If I may send you a picture?)

(Sure.)

Instantly, an image comes up of grayish colored slugs, all swimming around in a giant pool. But not a human sized pool. Then, a closeup of an individual slug. I don't know if it's him, or just a generic image. It's very disconcerting, and if I had control of Zach's body, I might have wanted to vomit just then.

Tolgar waits for me to get a hold on myself before continuing. (In our natural state, we are blind, nearly deaf, and quite helpless. Fortunately, we have evolved to become parasites, so by entering the ears-and then the brain-of another species, we can experience the senses that you humans take for granted.)

He sounds a little bitter about this, and I feel my own bitterness. After all, it's not like I have a body of my own.

(With the whole not being an alien parasite thing, I'm closer to you than you might think,) I point out.

The idea of myself as a parasite-although completely involuntary-is something that I have thought about on many occasions. But I would have used the term "body snatcher" instead.

Tolgar takes a minute to process this. (Yes...taking a different body every day certainly has its similarities to what we do as Yeerks. Except that we take one host for extended periods of time, and the host is aware that we are present.)

I have a million questions based on this information, but the first one that comes out of my head is, (What's a Yeerk?)

(That's what we are,) Tolgar explains. (Zach, the human whose body we are sharing for the next twenty-three hours and fourteen minutes, is my host. As long as I am here, he is what we Yeerks refer to as a Controller. Because his body is being controlled by me, or another Yeerk.)

The idea that an alien can take over someone's body like that is so horrifying that it makes what I do seem like nothing. Like taking a used candy wrapper off the ground. Insignificant. Especially if Zach is aware that Tolgar is there. And is unable to do anything. At least with me, the person disappears while I'm there.

Even though Tolgar can't read my thoughts, he can feel my emotions and my disgust at what he does. (I will have you know that Zach is what we call a voluntary Controller. He is happy that I'm there.)

(Why?)

The question may sound rude, but it's genuine enough. Who would choose this-this torture?

(I help him,) Tolgar explains. (I am not going to reveal intimate details about my host's life to you. You may be residing in him for the remainder of the day, but as long as I am there, you are not living his life, and you most certainly are not him.) He says this defensively. (What I will say is that I provide Zach with companionship. Emotional support. Additionally, I give him control of his body when he asks for it.)

(I don't suppose that privilege extends to me,) I groused.

(Seeing as you're not him, no. Remember this, A. He consented to me living in his brain. He did not consent to you. Nor, as we both know, did anyone else whose lives you have stolen.)

I send Tolgar a mental glare, even though what he's said is technically true. (Unlike you, I can't help what I do. Seriously,) I add, sensing his disbelief. (Whether I want to or not, each day, I wake up in a new body. No one consulted me on this. It just happened. I can't make it stop. And if I tried to kill myself and end it that way? Well, I'd probably just end up killing that poor kid's body, and landing in another one.)

Tolgar can sense the logic behind what I've told him. (I am still here with Zach's consent. You are not.)

I can feel something that Tolgar isn't saying. (You may be, but there's more than just you. The Yeerks in the pool. And there may be other pools. How many of you are living inside humans?)

Even as I say this, I remind myself that it can't be THAT many. I mean, in all of my fourteen years of changing bodies every day, this is the first time I've ended up in the body of a Controller. Sure, there are way more kids on the planet-even in this country-than I could possibly inhabit in my lifetime, let along as a kid or teenager. But still. If Yeerks were that widespread, wouldn't this have happened before? I do the math. Three hundred and sixty-five days in a year. I'm fourteen years old. Okay, let's use thirteen, because I don't know how long I have actually lived as a fourteen year old. My memories go back to age five. That means nine years. Nine times three hundred and sixty-five. That's...

Well, I can't do math that well in my head, and I don't want to ask Tolgar. Okay, use ten instead of nine. It's more than three thousand and six hundred. So, let's say 3500. That's how many people's bodies I've lived in, since I can remember. Wouldn't at least one of them have been a Controller if there were so many Yeerks on the planet?

Unless they were limited to one area, or were new to the Earth. But no, they couldn't be THAT new. Zach had been a Controller for two years.

(Where are we, anyway?) I ask Tolgar.

(Why?) he asks me, suspicious.

(I'm trying to figure out why I've never been in the body of another Controller before today,) I admit.

Tolgar hesitates before replying. (We're in southern California,) he tells me.

I've been there before. On numerous occasions. But never inside a Controller.

Well, maybe it was the odds catching up to me. Maybe it had to happen sooner or later.

(So, I'm a body snatcher, and you're a Yeerk. And for the next twenty-three hours or so, we're stuck with each other. This is gonna be fun,) I say, a little sarcastically.

He laughs, but the laugh isn't unkind.

(Given that humans sleep for eight hours, and Zach tries to get nine each night, it's closer to fourteen hours at this point,) Tolgar tells me.

(So, what exactly does he do while you're in control of his body?) I ask Tolgar. (I'm going stir crazy already.)

(As I told you, I give Zach control throughout the day, and besides, he has long since gotten used to my being in charge. We talk fairly often, and as he's still aware of his surroundings, he can still observe his surroundings. He's paid a lot more attention in class as a result.) Tolgar sounds proud of this fact.

I give him a mental shrug. (Hey, if it works for Zach, I'm not going to interfere. Not like I can, anyway.)

(No, you can't,) Tolgar informs me.

(So, when do I get control of Zach's body?) I ask Tolgar.

(You don't.)